# RUSTSEC-2026-0183: Potential undefined behavior when calling Remote::list()

> Calling Remote::list() on a remote with no references causes undefined behavior via null pointer dereference, potentially crashing the application.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 May 2026

## What is RUSTSEC-2026-0183?

RUSTSEC-2026-0183 is a vulnerability in git2, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When calling `Remote::list()` for a remote of a git repository, when that remote does not advertise any references, git2 passes a null pointer to the unsafe function `slice::from_raw_parts()`. Based on the safety section documentation of function, data must be non-null even for slices of length zero. Thus, the use of a null pointer leads to undefined behavior.

## Which versions are affected by RUSTSEC-2026-0183?

1 open source package ship an affected version, including git2.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `git2` | crates.io | From 0.0.0-0 | 0.21.0 |

## How do I fix RUSTSEC-2026-0183?

Upgrade git2 to 0.21.0 or later.

## Is RUSTSEC-2026-0183 being exploited?

There is no known exploitation of RUSTSEC-2026-0183 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for RUSTSEC-2026-0183 and fix it if it is affected.

What it is: RUSTSEC-2026-0183 is a vulnerability in git2, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of RUSTSEC-2026-0183 in the wild and no public exploit code.

Affected packages and fixed versions:
- git2 (crates.io): affected from 0.0.0-0; fixed in 0.21.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/RUSTSEC-2026-0183/ (Markdown: https://insights.sbomify.com/RUSTSEC-2026-0183/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/RUSTSEC-2026-0183

---
From sbomify Insights: https://insights.sbomify.com/RUSTSEC-2026-0183/
Summaries are generated and may contain mistakes; the official description above is the record.